In the field of solid state lighting (SSL) sources there is a growing tendency to devise modules, such as LED modules, with geometries such that they allow standardized mechanical interconnection, in order to simplify the installation of systems and the interchangeability of parts. For example, the positions of the LEDs and screw holes are currently undergoing standardization by Zhaga. The name “Zhaga” has been given to a collaborative consortium of companies in the lighting technology industry, set up with the aim of facilitating interchangeability of solid state lighting sources, such as LED sources, made by different manufacturers, in order to facilitate, for example, general lighting technology applications.
In various solutions, the characteristics of thermal coupling between the module and the mounting surface may be affected by the ways in which the lighting module (which may have a substrate formed by a structure similar to that of a printed circuit board (PCB), with a metal base for example) is fixed to the mounting surface (which may be a heat sink or a lighting system, for example). For example, the high thermal power densities generated by arrays (clusters) of LEDs may give rise to mechanical stresses in the substrate of the module; if the module is fixed to the mounting surface at certain isolated points only, substrate deformation phenomena may occur, such that the contact surface is reduced and the performance in terms of heat dissipation is adversely affected.
In order to overcome these drawbacks, it is possible to make use of rigid casings (which are rather bulky) and/or to add further holes for fixing the substrate, so as to improve the pressure distribution. Leaving aside any other consideration, the latter solution may be impracticable if the lighting system and/or the heat sink are already provided with mounting holes according to standardized solutions, thus making it necessary to create further fixing holes.